I recently had the pleasure of interviewing Mark Lien LC, CLEP, CLMC, HBDP, LEED BD&C, Director of Government and Industry Relations at OSRAM SYLVANIA and chair of NEMA Light Source Section. The topic: IES-TM-30, which proposes a new method of color evaluation, including new metrics to express color fidelity and saturation. I’m happy to share his responses with you here. The interview informed an article I wrote for the January 2016 issue of tED.
DiLouie: The Illuminating Engineering Society recently published TM-30, a new method for evaluating color quality of light sources. Will your company publish product information based on TM-30? Yes or no, why are you taking this position? If yes, when is that expected to happen?
Lien: We have had requests already from customers and can supply TM-30 information on our products. The TM-30 standard was approved by the IES as a concept worthy of evaluation by our industry. It is likely to evolve, so at this time it is premature to publish numbers or to use it in regulations, etc. CRI is a global standard and whatever replacement or alternative the industry agrees to needs to be global. The CIE is reviewing TM-30 now. They may accept it as is, modify it, or reject it in favor of some other metric. The recent CIE Position Statement stated ‘the CIE supports the study of the recently published IES[1] Technical Memorandum TM-30.’ The IES Position Statement states, ‘the issuance of TM-30-15 will enable the international lighting community to carefully evaluate it.’ We are early in the evaluation process. CRI has been with us for over 50 years. It is likely we will have to live with whatever metric we finally adopt for many decades. We need to make this new metric not just better than CRI, but the most useful we are capable of developing.
DiLouie: In a nutshell, what does TM-30 propose as a method?
Lien: This is a big nut but so to be brief I must over-simplify the method. TM-30 replaces the CRI Ra metric with another metric called Rf. The Ra number typically uses 8 colors for comparing a light source to a reference source. TM-30 would typically use 99 color evaluation samples adding a second metric for saturation or gamut. Ra and Rf are fidelity measurements. A full evaluation of color quality is more complex than just fidelity. It should be relevant to the application, and at least include color saturation in addition to the color fidelity metric. Our industry has acknowledged that CRI was incomplete by itself and that it did not address consumer preference. Consumers often prefer more saturated colors. When the saturation, Rg metric, goes up then the fidelity metric decreases. That is why regulators should be very careful about mandating fidelity levels, as this would limit preferred customer options. TM-30 also provides a new graphic for a visual evaluation of the source.
DiLouie: What market problems—barriers to adoption—will TM-30 solve in relation to LED lighting?
Lien: Hopefully, TM-30 will result in research on consumer color preference that will shift us away from fidelity based requirements that do not address what consumers prefer. These requirements were written with good intentions to keep poor ‘quality’ products out of the market, but fidelity metrics are only one aspect of color quality and light sources with very high fidelity or CRI can be unappealing to consumers. In some studies, the lower CRI products were preferred. Kodak made consumer films with higher saturation as customers liked very blue skies, warm fall leaves, etc. They made high fidelity films for inspection areas, dental labs, etc. where colors needed to match and be evaluated against a reference illuminant. Light sources are similar. Customers need and want some variation in color saturation to enhance specific applications and as a matter of preference.
DiLouie: How would adoption of TM-30 benefit specifiers, owners, etc. of LED lighting?
Lien: The hope is that TM-30 will better identify user and application based preferences. More data and research is needed in this area. TM-30 has sparked this conversation and some new research has already begun.
DiLouie: CRI is popularly used. While TM-30 may offer a superior method for evaluating color, it’s also more complex to use by specifiers and owners. Do you believe the construction industry will get behind TM-30 in a big way?
Lien: Ask anyone outside of the lighting community what CRI is and most will return a blank stare. CRI is not understood or used outside of our industry and not always understood within our industry. TM-30 is even more complex. Specifiers would benefit the most from a better color metric as they could better predict or control the appearance of their designs. As industries evolve, they increase in complexity. For example, the current IES Handbook is 40% larger than the preceding version. SSL has accelerated complexity with sources shifting into digital electronic devices. The complexity has resulted in more specialization in controls, chips, optics, drivers, software use and development, codes and standards, etc. TM-30 will be difficult to explain to some retail consumers who, for the most part, never knew what CRI meant. They know what they like but not the technical aspects of light and color.
DiLouie: Past efforts to replace CRI were hampered by a perception that manufacturers would not embrace change. Do you believe, with the popularity of LED sources, that the industry will get behind TM-30 in a big way?
Lien: The way TM-30 is proposed now does not cost manufacturers in terms of additional testing. Packaging may eventually include whatever new metric is adopted, but that could be phased in to minimize expenses or could be made available online. Manufacturers ultimately will embrace whatever helps their customers because they will buy more from the company that best meets their needs. Costs and investments need to be justified but that does not appear to be a barrier here. Before manufacturers get behind TM-30 ‘in a big way,’ we need an industry consensus on it as a global standard.
DiLouie: One theoretical advantage of TM-30 is that manufacturers will have incentive to innovate and develop precise spectral output. What are the benefits of this?
Lien: TM-30 presents the opportunity to differentiate fidelity from preference. We may better understand ranges of preference and what customers want for specific applications. With LED’s, we now have the ability to create light sources with increased spectral options to improve the appearance of applications and to provide even more opportunity for human centric lighting. A colleague has coined the term ‘spectral freedom.’ If we are no longer restricted by mandated fidelity metrics, innovation will result. OSRAM SYLVANIA is still evaluating the TM-30 metrics and will be testing them to determine whether they offer clear advantages to our customers, and especially because the move from existing CRI to TM-30 metrics will affect the whole standardization world where light quality demands are defined, like in buildings for example.
DiLouie: What’s in it for distributors with TM-30? Why should they care? What do they need to know and do to capitalize on it?
Lien: Most education in the lighting industry is done at manufacturer training centers. They will need to teach new metrics to distributors as well as specifiers including design and build electrical contractors, architects, interior designers, lighting designers, and of course, their own employees. Distributors benefit when they bring value to their customer. Understanding whatever new metric we adopt, and being able to explain it to their customers, will enhance their credibility and value. TM-30 has more momentum than any of the over twenty other metrics that have been proposed globally over the past decade. Distributors should have a general understanding of it but, as it is not mandatory and since the details may change, they may want to wait until an industry consensus is reached.
DiLouie: If you could tell the entire electrical industry just one thing about IES-TM-30, what would it be?
Lien: The standards that affect the lighting community are created by volunteers in the IES, ASHRAE, NEMA, etc. These hard working committee members have day jobs which seldom allow them to focus just on standards development. As a result, standards are developed more slowly than the pace of change our industry is experiencing. We need more people to get involved and actively participate to keep up with pace of change. If the change outside of our industry is quicker than the change within our industry, we will lose to others who can move to fill in the gaps. We will not control our own destiny. If you are reading this, it means you. I recommend getting involved in shaping the discussion of color and all of the other standards and regulations that impact us, or we are abdicating this role to someone else who may not have your best interests at heart.
